## Algebra: A Combined Approach (4th Edition)

$3y^5+7y^5-2y^2-y^2=10y^5-3y^2$
Organise pairs of coefficients such that the coefficients will correspond to $10$ and $-3$. $3y^\square+7y^\square-2y^\square-y^\square=10y^5-3y^2$ $3+7=10$ $-2-1=-3$. So $3y^5+7y^5=10y^5$ $-2y^2-y^2=-3y^2$ $3y^5+7y^5-2y^2-y^2=10y^5-3y^2$.